Connection of a micro-tube to a structure

ABSTRACT

The recess ( 12 ) between the main connecting part ( 8 ) and a collar ( 9 ) contains a toroidal or otherwise shaped sealing ring or joint ( 3 ) and the end of a tube ( 1 ) incorporating an outer flange ( 2 ), whose thickness becomes zero at the crushing bulge ( 4 ) of the sealing ring ( 3 ). An excellent seal is ensured at this location, even for pressurized fluids, and the assembly can easily be dismantled.

DESCRIPTION

[0001] The present invention relates to the connection of a micro-tubeto a structure.

[0002] The tubes in question can be flexible, rigid or semi-rigid, havea very small diameter of approximately one millimetre and are able tocarry gaseous or liquid fluids at a pressure of several bars.

[0003] The sealing at the ends of such micro-tubes is not then easy toensure in an appropriate manner and requires either crimping, whichreduces the opening cross-section of the tube, or complicated and costlyfitting, or bonding, which does not permit an easy replacement of thetubes.

[0004] The present invention proposes a simple, reliable anddismantlable connection. It is characterized in that it comprises anelastic, cambered joint surrounding the micro-tube, a flange fashionedaround the micro-tube tapering out of the micro-tube and extending up toa bulging circumference of the joint, and a collar on the structure,joined to such structure whilst forming a recess in which the joint isheld between the faces of the recess on which it bears, the flangebearing on one of said faces.

[0005] The flange bearing on one of the faces of the recess ensures agood sealing at this location and this is perfected by the joint which,compressed in the recess in the axial direction of the micro-tube,presses the flange against said face of the recess, whilst offering asupplementary sealing ring around the flange.

[0006] Other features, characteristics and advantages of the inventionwill be described with reference to the attached drawings.

[0007]FIG. 1 shows in cross-section an embodiment of the invention,FIGS. 1A and 1B show two variants of FIG. 1 and FIGS. 2 and 3 show anembodiment of the turned-up flange.

[0008] A micro-tube 1 is shown in FIG. 1 and terminates in a turned-upflange 2 held in the connection forming the subject matter of theinvention. The turned-up flange 2 is in one piece with the micro-tube 1.The connection of the microtube 1 also comprises a sealing ring or joint3, which can be toroidal in the free state and has opposing bulges 4 and5 bearing on two faces, respectively 6 and 7, of a main structural part8 and a collar 9. The main structure part 8 carries a channel 10extended by the micro-tube 1. The turned-up flange 2 bears on thesurface 6 of said main structural part 3, the joint 3 is placed on theturned-up flange 2 and the collar 9 is placed on the joint 3 in order tocompress the latter and secure the turned-up flange 2 whilst maintainingit on the face 6. The main structural part 8 can be joined to the collar9 by a thread 11 on their surfaces making it possible to join themdirectly by screwing and to move them together as desired by regulatingthe height of a recess 12 defined by the faces 6 and 7. The collar 9 andstructure 8 can be pressed or moved together by any linking means otherthan direct securing obtained with the aid of the thread 11 referred toin exemplified manner here.

[0009] The joint 3 is introduced onto the micro-tube 1 and bears on theturned-up flange 2. Its small diameter is substantially equal to theexternal diameter of tube 1 and the turned-up flange 2 taperscontinuously towards the outside (on moving away from the micro-tube 1)and is cancelled out at a diameter corresponding to that of the bulge 4.

[0010] In a preferred embodiment, the mean diameter of the toroidalsealing ring 3 is approximately equal to the external diameter of theturned-up flange 2, so as to ensure a pressure on said flange 2 and thesealing between said flange and the face 6 of the structure 8.

[0011] As the joint 3 is pressed by the collar 9, as a consequence itpresses the turned-up flange 2 against the opposite surface 6, thusopposing a detachment under the pressure of the fluid flowing throughthe micro-tube 1 and channel 10 of the main part 8 and tending toseparate them. Sealing is mainly produced at the bulge 8 and experiencehas proved that it remains for fluid pressures reaching 10 bars. In thecase of a high fluid pressure, it is advantageous to place the joint 3in a recess 14, 15 made either on the face 7 of the collar 9, or on theface 6 of the structure 8, so that the areas round the correspondingbulge 4 or 5 of the joint 3 penetrate the same and the radial expansionof the joint 3 is in this way combatted. The recesses 14 and 15 areillustrated in FIGS. 1A and 1B. Unlike the recess 12, they providesupport to the periphery of the joint 3. Normally the main structuralpart 8 is used for multiple connections and has numerous channels 10connected to the same number of micro-tubes 1 and the recess 12 is wideenough to include the network of connected micro-tubes 1. A circle ofscrews is then used for joining the collar 9 to the main structural part8. In other variants, the collar 9 could have an external thread and themain part 8 an internal thread, unlike what is shown here, or otherknown means for creating these two parts and for moving them together.

[0012] A production method for the turned-up flange 2 will be describedrelative to FIGS. 2 and 3. The micro-tube 1 is inserted in a slot 16 ofa die 17 in such a way that its end points somewhat to the outside. Aconical punch 18 is introduced into the projecting end and widens it. Aflat punch 19 (which can be an opposite face thereof) is then pressedonto the upper face of the die 17 crushing the end of the micro-tube 1against said surface, which gives the turned-up flange 2 of FIG. 1.

[0013] This process is suitable for most micro-tube materials. However,others can be used, more particularly if the micro-tube 1 is flexible.It can then be hardened by heating or some other means, as a function ofits composition, once the deformation has taken place. It is alsopossible to use glass micro-tubes. The aforementioned process will beaccompanied by a heating operation in order to soften the glass.

[0014] Generally the flanges are produced by a permanent materialdeformation process.

[0015] The sealing ring or joint 3 illustrated is toroidal.Cross-sections other than circular are suitable provided that they havebulges bearing on the opposite faces 6 and 7 of the recess 12 in orderto press the flange 2 against the face 6. In the same way a flange 2 isshown stopping at the diameter of the joint 3 corresponding to thegreatest height (between bulges 4 and 5), but it is unnecessary toprecisely respect this condition and the flange 2 could be slightlywider or narrower. However, the configuration shown is preferred.

1. Connection of a micro-tube (1) to a structure (8), characterized inthat it comprises an elastic, cambered joint (3) surrounding themicro-tube, a flange (2) fashioned around the micro-tube tapering out ofthe micro-tube and extending up to a bulging circumference (4) of thejoint, and a collar (9) on the structure, joined to such structurewhilst forming a recess (12, 14, 15) in which the joint is held betweenthe faces (6, 7) of the recess on which it bears, the flange bearing onone of said faces.
 2. Connection according to claim 1, characterized inthat the collar and the structure are pressed towards one another withthe aid of a linking means.
 3. Connection according to claim 1,characterized in that the flange (2) is produced in one piece with themicro-tube (1).
 4. Connection according to claim 1, characterized inthat the recess (14, 15) is designed so as to support a periphery of thejoint (3).
 5. Connection according to claim 1, characterized in that therecess (12) includes several micro-tubes (1).